A chemical vapor deposition reactor is already known from the patent U.S. Pat. No. 4,961,399. This document describes an epitaxial reactor for processing a plurality of semiconductor wafers by exposing them to a reactive gas flow. Said reactor has a planetary graphite substrate holder in a process chamber, which is the space where the gas flow is in contact with the wafers and is constituted by a cylindrical body, having a vertical axis and surrounding the planetary substrate holder as closely as possible. The cylindrical body is hermetically sealed at its lower and upper parts by bottom and top plates. A roughly flat cover covers this arrangement. An inlet for the reactive gas flow is located in the center of the cover, opposite to the planetary substrate holder. This inlet introduces the reactive gas flow into the process chamber via several concentric funnels whose ends flare downwardly. For opening the reactor, the cover is lifted to allow access to the interior of the process chamber. The substrate holder is surrounded by a hollow quartz ring provided with apertures around its circumference, which is an exhaust arrangement in which tubes end, via which the reactive gas flow can exit. An additional gas flow formed of hydrogen is fed in the space disposed between the cylindrical body and the quartz ring, in order to prevent the reactive gas flow to penetrate and contaminate said space.
In the field of manufacturing semiconductor devices including depositing epitaxial layers on semiconductor material of the III-V chemical group, the above described reactor does not solve a certain number of problems.